Resinous plastic pirn



March 24, 1959 T. G. CRAWFORD RESINOUS PLASTIC PIRN Filed Jan. 27, 1956 United States Patent RESINOUS PLASTIC PIRN Thomas G. Crawford, Hampton, S.C., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 27, 1956, Serial No. 561,781

4 Claims. (Cl. 242-41832) This invention relates to pirns, bobbins and like members for collecting textile fibers, prepared from resinous plastics.

In the textile industry great numbers of pirns and bobbins are employed for winding thereon textile fibers. While numerousmaterials and various forms of pirn constructions have been employed for winding cotton, wool and similar animal fiber textiles, the problem of handling the high tenacity synthetic resin fibers such as nylon, polyester, and acrylonitrile polymer fibers has caused considerable difliculty. These synthetic textile fibers have great tensile strength, often of from 4 to 8 grams per denier, and conventional pirn and bobbin materials have either collapsed or have had their surfaces cut or damaged so that repairs have been required after every use thereof.

It has been found undesirable to employ metal pirns or bobbins wherein the fibers are in direct contact with such metal because the metal will cause discoloration or staining of the fibers. In some cases, the surfaces of metal pirns have been covered with paper or cardboard in order to prevent fiber discoloration. However, owing to the high strength of the fibers, the paper or cardboard is badly damaged after several uses'and, accordingly, the paper must be stripped and the pirn or bobbin reconditioned after a few uses. It will be appreciated that this is expensive and time consuming.

Pirns and bobbins furthermore are subjected to considerable abuse in service. Thus, the pirns with or without fibers wound thereon may be thrown or tossed around and are subject to heavy loading in shipping so that the ends are frequently damaged. Bobbins and pirns available heretofore have been so constructed that the ends at which the damage occurs are not easily repaired and, consequently, the entire pirn may need to be discarded or reconditioned. g

It is desirable to have available as light a pirn as is possible for the service. The pirns are shipped back and forth from the spinning plant to the weaving plant and the shipping charges are based on the weight thereof. Any excessive weight of the pirn is undesirable because of increased costs.

. The object of the present invention is to provide a relatively light weight pirn which will withstand repeated use for winding synthetic resin fibers, the pirn composed of a high strength thin walled laminated resinous tube and press fitted molded resinous end members and a spindle bearing member. a

A further objectof the invention is to provide a light weight pirn comprising molded resinous end members press fitted, into a high strength laminated tube.

A further object of the invention is to provide a pirn comprising a thin walled, light weight tube of laminated paper treated with a:selected phenolic resin which provides a very high strength so that the tube will resist crushing and deformation when wound with synthetic fibers. J p

Other objects of thexinvention will in part be obvious and will in part appear hereinafter. i I.

V 2,879,010 Patented Mar. 24, 1959 For a better understanding of the nature and objects of the invention, reference should be had to the following detailed drawing made to scale, in which:

Figure 1 is a vertical cross section through one modification of a pirn;

Fig. 2 is a bottom end view of the pirn of Fig. 1;

Fig. 3 is a vertical cross section through another modification of a pirn; and

Fig. 4 is a bottom end view of the pirn of Fig. 3.

In accordance with the present invention, I have produced a light weight pirn having considerable strength and impact resistance so that the pirn may be repeatedly used in winding all kinds of textile fibers, both natural and synthetic fibers. In practice, these pirns have been reused scores of times with little or no damage to the surface'of the pirn. Furthermore, the pirns are provided with high impact strength end members which are press fitted into the ends of the tube or barrel. Such end members comprise a molded resinous composition which will withstand dropping and other abuse. In the event that an end member is damaged, it may be readily replaced in a few minutes by forcing out the damaged end member and pressing a new one into the end of'the tube.

More generally, the pirns of my invention comprise a thin walled tube or barrel prepared by wrapping paper treated with selected phonolic resins on a mandrel and curing to a thermoset state. The tube is machined and ground to precise internal and external diameter, ordinarily within the range of 1.5 to 2.5 inches outside diameter, the wall thickness of the tube being from A; to inch. The drive end member and the upper end member to be fitted into the two ends of the tube are provided with a reduced diameter portion that is from 5 to 10 mils greater than the inner diameter of the tube. These end members are then press fitted into the tube and will remain in place therein under all conditions of use. A thermoplastic adhesive such as polyvinyl acetate may be applied to retain the end members in place. In addition, a spindle bearing bushing is ordinarily pressfitted within the tube at a point intermediate its ends for engagement with the upper end of the spindle on which the pirn is to be fitted for rotation therewith. This bushing may be prepared from a thermosetting resinous molded material similar to that employed for the end members or it may be prepared from a tough thermoplastic, such as nylon polymer.

Referring to Figs. 1 and 2 of the drawing there is illustrated one form of pirn 10 produced in accordance with the present invention. The pirn 10 comprises the tube 12 of laminated paper and phenolic resin having the high strength and other characteristics required for this purpose. The interior of the tube may be machined or ground to a diameter 14. The interior of the lower end of the tube 12 is machined to remove about half the tube wall thickness to provide an internal ofiset diameter 16 somewhat greater than the diameter 14 and extending to a land 18 about half an inch from the end.

A drive end 20 comprising high impact strength molded material is force fitted into the lower end of the tube 12. The drive end is of an exterior stepped cylindrical outer wall configuration and comprises a lower portion 22 having a normally free diameter about 10 mils greater than that of the ofiset diameter 16. Within the lower portion 22 is a generally hexagonal open-ended recess 24 comprising three arcuate lengths 23 joined by three fiats 25, as shown in Fig. 2 in particular. The recess 24 terminates in a flat upper surface 26 which provides for resting the pirn on the whorl of a spindle. Extending above the flat surface 26 is a smaller cylindrical aperture 28 which has at its upper end a fiat surface 30 in which are provided two rectangular shaped slots 32 which are adapted to engage with a key or pin in the drive spindle. Above the flat surface 30 is a still smaller cylindrical portion 34 which, in turn, terminates in a conical wall 36 which flares. outwardly therefrom. The drive end has a relatively smaller diameter exterior surface 38 which is of a diameter of from to mils greater than the inner diameter 14 of the tube. A bevel 39 is provided at the extreme upper end of the diameter 38 to center and to enable the drive end 20 to be placed within the lower end of the tube 12. The bevel enables the drive end to be pressed into the tube more readily. Otherwise, crushing of the edges of ends or the tube would occur when the end is being pressed in before proper slipping engagement therebetween takes place.

It will be noted that the spindle bearing cylindrical portion 52 is placed above the point at which the exterior diameter 41 engages the tube wall. It has been found that this relationship prevents deflection and binding of the spindle therewith.

There is disposed within the interior of the tube 12 at a point intermediate its ends, ordinarily close to the upper end of the pirn, a bushing member 40 to enable the pirn to be centered and guided on a driving spindle. The bushing 40 of an exterior diameter 41 comprises an internal aperture of progressively stepped conformation beginning with a conical portion 42 which slopes from the exterior diameter 41 at its lower end inwardly to a first large cylindrical portion 44. The cylindrical portion 44 extends upwardly until it meets a second conical portion 46 which, in turn, leads to a long cylindrical portion 48 and this, in turn, terminates in an upper conical portion 50 which ends in a cylindrical portion 52 of the diameter of the spindle with which the pirn is attached to cooperate. It will be observed that the series of conical end cylindrical portions 42, 44, 46, 48, 50 and 52 are progressively smaller. The purpose of these is to assist guiding and fitting the bushing when it is being placed on the spindle tip, with the least effort. The outermost diameter 41 of the bushing is from 5 to 10 mils greater than the diameter 14 in order that the bushing may be press fitted into place in the tube and it will stay where located under all conditions of service. A long exterior cone surface 54 extends from the diameter 41 to the upper end of the bushing.

The upper end of the tube 12 is provided with an internal offset portion 56 about inch in depth which terminates in a land 58. Within the upper end of the tube there is press fitted an upper end member, or, as it is commonly called, an identification end, 60. The upper end member is composed of a high impact strength molded material. The upper end member 60 has an outer diameter 62 which is from 5 to 10 mils greater than the offset 56. The end member then has a slightly reduced diameter 64 extending below the diameter 62 and it is from 5 to 10 mils larger than the diameter 14 of the tube. A bevel 66 is provided at the lower end of the upper end to enable it to be readily press fitted into the upper end of the tube as shown in the drawing. The upper end 60 has a central aperture comprising a relatively larger diameter portion 70 joined therewith as shown.

The pirn 10 is illustrated in position on a spindle 30 which comprises a cylindrical shaft 82 terminating in an upper tip 84 extending slightly beyond the upper end of the bushing 40. The shaft 82 is slightly smaller than the bearing portion 52 of the bushing. Ordinarily, a difference in the diameters is such as to provide clearance of 5 to 10 mils between the spindle and the hearing 52. The spindle 80 is driven by a shaft 86 which is connected to a whorl or drive 88 having surfaces which engage with the flats 24 of the drive end recess. The whorl has a flat upper surface 90 on which the flat surface 26 of the end member rests and it thereby supports the entire pirn 10. If desired, a pin 92 passing through the spindle. shaft 82 may be employed, to support and drive the pirn in place of employing the whorl member 88.

An important feature ofthe pirn construction is the fact that the end members are of a maximum diameter less than that of the tube and are inset into the ends of the tube 12, so that no threads can be caught between the tube and the ends 20 and 60, as would occur if the ends were driven in flush against the ends of the tube. Tubes were prepared by me wherein the ends had a maximum diameter equal to the outer diameter of the tube, and when driven into the ends of the tube presented a peripheral joint in which fine threads did catch.

A pirn with somewhat different features is illustrated in Figs. 3 and 4 of the drawing. The pirn comprises a tube 102 having an exterior diameter 103 and an interior diameter 104. The lower end of the tube 102 is internally chamfered to provide a land 106 and an offset portion having a diameter 108. A drive end member 110 is press fitted into the lower end of the tube 102. The bottom of the drive end has an open drive end recess 112 of octagonal configuration, as more clearly evident in Fig. 4. The recess comprises four flat portions 114 with intervening arcuate portions 116 and it terminates in a horizontal surface 118. The exterior of the drive end comprises a stepped configuration with a lower portion with a surface 120 and an upper portion with a surface 122, each portion being slightly larger than the diameters 108 and 104, respectively, whereby the drive end member may be force fitted into the lower end of the tube much as described in connection with Fig. l. The interior of the drive end member 110 has a relatively large cylindrical aperture 124 extending above the surface 118. The outer periphery of the extreme upper end of the drive end member is provided with a bevel 126 for the purpose set forth previously.

Intermediate the ends of the tube 102 is disposed a bushing member 130 which comprises an outer diameter 132 slightly greater than the internal diameter 104 of the tube so that the bushing may be press fitted into place. The central interior portion of the bushing 130 is provided with a lower relative large cylindrical aperture 134, which may be beveled at its lower end similar to 42 in Fig. l, which terminates in a sloped portion 136 which, in turn, leads to a cylindrical portion 138 equal to the diameter of the spindle on which the pirn is to be fitted. An exterior slope 140 extends from the diameter 132 to the upper end of the bushing.

The upper end of the tube 102 is internally chamfered to provide a land 142 and an internal offset of inner diameter 144. An upper end member 146 comprising a lower portion having an exterior diameter 148 and an upper portion having an exterior diameter 150, both slightly larger than the diameter 104 and diameter 144, respectively, is force fitted into the upper end of the tube. A bevel 152 is provided around the exterior periphery of the bottom of the upper end to enable the force fitting of the upper end 146 to be more readily carried out. The interior portion of the upper end is provided with an upper cylindrical aperture 154 and a second cylindrical aperture 156 of slightly larger diameter as illustrated.

It will be observed that in all of the figures shown, the drive end member and the upper end in all cases extend beyond the ends of the respective tubes into which they have been force fitted. Thus, in case the pirn, with or without a winding of textile fibers thereon, is dropped, the tube or barrel itself will not be liable to be damaged and the molded ends will take the major impact of the blow. If either the drive end or the upper end of the pirn is damaged or broken, it can be readily extracted and a new molded member can be readily inserted in a few minutes. In the construction of Figs. 1 and 3, the exposed ends of the tube 12 and 102 can be engaged by a jig having an aperture slightly larger than the diameter 16 or 110, while the drive ends or upper ends are being extracted through such aperture in the 1g. If a thermoplastic adhesive has been applied, the

ends maybe heated to about 140 C. before the ends are extracted.

The press fitted ends and bushings put the tube in tension in each instance. Therefore, the tubes will better withstand the crushing force of the textile fibers wrapped thereon than will a tube in which the ends are simply glued or otherwise fitted without press fitting. It has been found that the portion of the drive end fitting into the tube where the tube wall is at its full thickness should have a length of at least /a the inner diameter of the tube, and preferably from 16 to A of the diameter. The chamfered or reduced portion of the tube, as 16 in the Fig. 1 configuration, is not considered in this proportion.

In all of the modifications of the pirns, the tubes used in practicing the present invention are preferably prepared from paper and a specific phenolic resin which enables Wrapped tubing of exteremely high strength to be produced without molding in a press. In particular,

outstanding results have been obtained when the applied phenolic resin is prepared by admixing the two following separate phenolic resins. The mixture of phenolic resins comprises (a) from 30% to 70% by weight of the reaction product derived by refluxing phenol and equeous formaldehyde in the proportions of one mole of phenol with from 1.30 to 1.4 moles of formaldehyde in the presence of sufiicient alkali hydroxide to produce a pH of from 9.3 to 9.7 in the mixture, the refluxing being continued from of an hour to 1.5 hours and then dissolved in substantially equal parts of water and alcohol to produce a varnish having from 40% to 60% resin solids, and (b) from 70% to 30% by weight of the resinous reaction product derived by refluxing phenol and aqueous formaldehyde in the proportions of one mole of phenol and from /2 to 1.28 moles of formaldehyde in the presence of alkali sufficient to produce a pH from 7.6 to 8.5 in the mixture, the mixture being refluxed for from 1% hours to 2 hours, the mixture being vacuum dehydrated at the end of the period to remove substantially all the water and thereafter the resin being admixed with from 1% to 3% by weight, based on the weight of the phenol, of resorcinol and from 0.5 to 1%, based on the weight of the phenol of aqueous alkali hydroxide at a concentration of from 2% to 5%. Paper, for example, 3 to 6 mil thick kraft paper has given good results, is impregnated with the mixture of phenolic resins to provide thereon phenolic resin equal to from 120% to 150% of the weight of the paper. The paper with the applied phenolic resin is passed through an oven or tower to remove the solvent therefrom and to advance it to a B stage wherein the paper has a greenness of from 7% to 14%. Greenness is determined by the test described in U.S. Patent 2,383,430. The paper so treated is wound on an 80100 C. mandrel using a hot roll temperature from 150 C. to 165 C. while being under a pressure of 8 to 10 pounds per lineal inch for 3.5 mil kraft paper. The mandrel with the resin treated paper thereon is baked for from 1% to 1% hours at a temperature of 145 C. to 155 C. The tube may then be striped from the mandrel and machined, as by grinding, to the desired internal and external diameter and cut to the desired length for a pirn.

The molded ends and the bushings may be prepared from high impact strength phenolic or melamine molding compound. Ordinarily, these compositions may be prepared by impregnating cotton fabric with a phenolic resin and chopping the treated fabric. A weighed quantity of the chopped resin coated fabric is placed in a mold and the desired member produced under a pressure of 3000 pounds per square inch at a temperature of 300 F. applied for five minutes. It will be understood that other temperatures and pressures may be employed for the molding operation. The end membersalso may be prepared from stable, impact resistant thermoplastic resins which may contain re-enforcing materials such as cotton, glass fibers, asbestos fibers, synthetic fibers, and the like. Suitable end members may comprise nylon polymers and cellulose acetate butyrate resin.

The following example, in which all parts are by weight, illustrates the preparation of a pirn in accordance with the following invention. Resin (a) was prepared by reacting 1080 parts by weight of phenol and 1245 parts of 37% aqueous formaldehyde. A solution of 38 parts of sodium hydroxide dissolved in 83 parts of water was added to the mixture. The mixture had a pH of approximately 9.5. The mixture was heated slowly until refluxing began and the reaction was continued under reflux for one hour. Thereafter a mixture of 100 parts of ethanol and parts by weight of water was added which produced varnish having a solid content of approximately 50% Resin (b) was prepared by reacting in a kettle 1080 parts of phenol and 1130 parts of 37% aqueous formaldehyde. A solution of 4% parts of sodium hydroxide dissolved in 8 parts of water was added. The pH of the mixture was approximately 7.9. The mixture was refluxed for 1.5 hours and then an aqueous solution of 7 parts of sodium hydroxide dissolved in 200 parts of water was stirred into the resin followed by adding 22 parts of resorcinol. The resulting varnish had a resin solids content of 53%. I

The two batches of resins (a) and (b) so produced were admixed, and 3.5 mil thick kraft paper was dipped therein and passed into a drying oven until enough resin to equal of the weight of the paper had been applied thereto. The greenness of the paper was approximately 10%. A mandrel at a temperature of 100 C. was then wrapped with 50 plies of the treated kraft paper under a tension of 9 pounds per lineal inch. The resulting wrapped unit was placed in an oven and heated for 1.5

hours at a temperature of C. The mandrel was then stripped and the resulting tube machined to an external diameter of two inches and an internal diameter of 1% inches. The total length of the tube being 11% inches. Thereafter a bushing was press fitted into the tube, and then molded ends as shown in Figs. 3 and 4 of the drawing all having the external diameter portions approximately 10 mils greater than the internal diameter of the tube were press fitted into the tube.

A great number of tubes corresponding to each of the several forms shown in the drawing, and other similar configurations, have been successfully employed for winding textile fibers, particularly high tenacity synthetic textiles thereon, with considerable success. Thus, these pirns have been reused many times in winding nylon fibers with no significant damage to the tube surfaces.

Even when yarn must be cut off with a knife under certain circumstances, the laminated plastic tube is not appreciably damaged. At most, fine scratches are produced which are easily smoothed off with fine sandpaper. The pirns of this example have a weight from 340 to 360 grams which is substantially below the weight of any metal pirns available at the present time.

It will be understood that the above description and drawing are only exemplary.

I claim as my invention:

1. A high strength, low weight pirn adapted to cooperate with a vertical spindle having a driving whorl to drive the pirn, the pirn consisting entirely of resinous plastics, comprising in combination, (1) a thin-walled high strength' tube of a given inner diameter, the tube comprising a plurality of plies of fibrous sheet material impregnated with a thermoset resin, (2) a molded driveend member force fitted into the lower end of the tube, the drive end member having a stepped, cylindrical outer wall configuration comprising a first upper portion of a diameter when free of from 0.005 to 0.01 inch greater than the inner diameter of the tube and a second lower portion of substantially greater diameter but less than the outer diameter of the tube, the drive-end member being force fitted into the lower end of the tube, the upper end of the first portion being beveled to enable it to be placed Within the tube and readily press fitted therein, the length of the first portion in contact with the inner diameter of the tube being at least a third of the inner diameter of, the tube, the second portion extending beyond the lower end of the tube, the second portion having walls defining a recess opening at the extreme lower end of the drive end member, the walls including engaging means to cooperate in driving engagement with the whorl of the spindle, (3) a molded bushing press fitted into and disposed entirely within the tube at a point intermediate its ends, the bushing having a central bearing aperture closely fitting the upper end of the spindle to be guided for rotation thereby, the bushing having an outer diametral portion when free which is from 0.005 to 001 inch greater than the inner diameter of the tube, the length of the diametral portion being at least /3 the inner diameter of the tube, and an inwardly converging beveled portion extending from the outer diametral portion which terminates at a diameter less than the inner diameter of the tube, the converging diametral portion enabling the bushing to be readily forced into position within the tube, and (4) a molded upper end press fitted into the upper end of the tube, the upper end comprising a stepped cylindrical outer wall configuration comprising a lower small diameter portion which when free is from 0.005 to 0.01 inch greater than the inner diameter of the tube and another portion of substantially greater diameter than the small diameter section but less than the outer diameter of the tube, the upper end being force fitted into the upper end of the tube, a bevel at the lower end of the small diameter section ending on a diameter smaller than the inner diameter of the tube to enable the upper end to be readily force fitted into the tube, the larger portion extending beyond the upper end of the tube, and the molded drive end, bushing and upper end comprising a high impact strength resin.

2. The pirn of claim 1, wherein the drive-end member recess comprises the walls forming a fiat horizontal surface whereby the pirn may be supported by said surface resting on the whorl, and a smaller central aperture extending upwardly from the horizontal surface entirely through the drive end member, the central aperture being larger than the spindle bearing in the bushing to enable the pirn to be tilted when lifted off the whorl.

3. The pirn of claim 1, wherein the molded bushing has walls defining an opening at its lower end substantially greater than the bearing aperture, and a sloping wall configuration between the opening and the bearing aperture to guide the end of the spindle into bearing aperture.

4. A high strength, lowweight pirn adapted to cooperate with a vertical spindle. having a driving whorl to drive the pirn, the pirn consisting entirely of resinous plastics, comprising in combination, (I) a thin-walled high strength tube of a given inner diameter, the tube comprising a plurality of plies of fibrous sheet material impregnated with a thermoset resin, (2) a molded driveend member force fitted into the lower end of the tube, the drive end member having a stepped, cylindrical outer wall configuration comprising a first upper portion of a diameter when free of from 0.005 to 0.01 inch greater than the inner diameter of the tube and a second lower portion of substantially greater diameter but less than the outer diameter of the tube, the drive-end member being force fitted into the lower end of the tube, the lower end of the tube having an oifset diameter portion matching the stepped outer wall configuration of the drive end member, the length of the first portion in contact with the inner diameter of the tube being at least a third of the inner diameter of the tube, the second portion extending beyond the second portion having walls defining a recess opening at the extreme lower end of the drive end member, the walls including engaging means to cooperate in driving engagement with the whorl of the spindle, (3) a molded bushing press-fitted into and disposed entirely within the tube at a point intermediate its ends, the bushing having a central bearing aperture closely fitting the upper end of the spindle to be guided for rotation thereby, the bushing having an outer diametral portion when free which is from 0.005 to 0.01 inch greater than the inner diameter of the tube, least V3 the inner diameter of the tube, and an inwardly converging beveled portion extending from the outer diametral portion which terminates at a diameter less than the inner diameter of the tube, the converging diametral portion enabling the bushing to be readily forced into position within the tube, and (4) a molded upper end press fitted into the upper end of the tube, the upper end comprising a stepped cylindrical outer wall configuration comprising a lower small diameter portion which when free is from 0.005 to 0.01 inch greater than the inner diameter of the tube and another portion of the upper end of the tube having an internal offset diameter matching the stepped cylindrical configuration of the upper end member, the upper end member being force fitted into the upper end of the tube, and the larger portion of the end member extending beyond the upper end of the tube, the drive end member, the bushing and the upper end member being molded from a high impact strength resinous material.

References Cited in the file of this patent UNITED STATES PATENTS lower end of the tube, the

the length of the diametral portion being at 

